The present invention relates to a fingerprint input apparatus that reads fingerprints and to a method for the same.
A person can be identified through fingerprint authentication. A fingerprint input apparatus is used for fingerprint authentication. The fingerprint input apparatus has a fingerprint reading function and the function of verifying a read fingerprint against a previously-registered fingerprint. A fingerprint sensor realizes the fingerprint reading function. The fingerprint sensor is pressed by a finger of a user to read the fingerprint thereof. When the acquired fingerprint matches with a registered fingerprint, the fingerprint verification is established. When the acquired fingerprint does not match with the registered fingerprint, the fingerprint verification is not established.
The technique related to the fingerprint input apparatus is disclosed in Japanese Patent Publication No. 2949007, JP-A No. 272886/1986, JP-A No. 225345/1993, and JP-A No. 161491/1996.
An improper press of a finger against the fingerprint sensor causes an erroneous fingerprint reading of the fingerprint sensor. Moreover, a failure due to moisture on a finger causes an erroneous fingerprint reading of the fingerprint sensor. An occurrence of a fingerprint reading failure results in degradation in the accuracy of fingerprint verification. When the accuracy of fingerprint verification decreases, the fingerprint verification becomes a non-established state even in the inputting of a correct fingerprint. When a significant failure in fingerprint reading occurs, the fingerprint authentication process may not be activated. In such a case, a user has to require a countermeasure against the cause of the fingerprint reading failure.
When a failure in fingerprint reading occurs, the conventional fingerprint input apparatus issues an alarm of a failure occurrence or displays re-execution of a fingerprint reading. However, the conventional fingerprint input apparatus does not notify a user of the cause of an occurrence of a fingerprint reading failure. When a user recognizes the occurrence of a fingerprint reading failure, he cleans the finger and changes the position on which the finger is pressed against the fingerprint sensor. This operation is performed by the user in response to an assumed cause of a fingerprint reading failure. That is, the user must take a countermeasure without recognizing the actual cause of a fingerprint reading failure.